Exploring the determination of the standard rate constant in electrochemical metal deposition: theory and experiment

Abstract

A detailed investigation of the electrochemical metal deposition was carried out using both simulation and experimental cyclic voltammetry (CV). Kinetic curves were developed to relate peak-to-peak potential separation (ΔE_p) to the cathodic charge transfer coefficient (α) and the standard rate constant (k⁰). From these curves, interpolation equations were derived to estimate k⁰, taking into account the effect of the transfer coefficients sum (α + β), whether equals to or different from 1. The validity of the equations was confirmed through the reduction of silver, copper and rhenium ions in various electrolytes, yielding k⁰ values of 14.51 × 10⁻⁶ m s⁻¹ for Ag⁺/Ag, 5.98 × 10⁻⁷ m s⁻¹ for Cu⁺/Cu and 10.59 × 10⁻⁸ m s⁻¹ for Re⁶⁺/Re. According to the Matsuda–Ayabe criteria for assessing electron-transfer reversibility, the Ag⁺/Ag and Cu⁺/Cu redox couples are regarded as quasi-reversible, while the Re⁶⁺/Re couple is classified as irreversible. The simulated CVs showed strong agreement with experimental results.